Retortable packaging laminate structure with adhesive layer

ABSTRACT

An adhesive resin composition comprising an ethylene/vinyl acetate copolymer, a styrene polymer resin, graft-modified polyethylene, a polystyrene elastomer and an ethylene/α-olefin copolymer in combination is disclosed. This adhesive resin composition shows an excellent adhesiveness between a metal and a thermoplastic resin. When this adhesive resin composition is used for bonding a polyester resin and a gas-barrier resin, a good bonding which is not degraded even by high-temperature heating can be attained.

This is a division of Application Ser. No. 07/563,351 filed Aug. 7,1990, now abandoned.

BACKGROUND OF THE INVENTION

(1) Field of the Invention

The present invention relates to an adhesive resin composition and alaminate comprising this resin composition as an adhesive layer. Moreparticularly, the present invention relates to an adhesive resincomposition giving an excellent adhesiveness between a metal and athermoplastic resin, and a metal/resin sheath laminate to be used for alaminate sheath cable, which is formed by using this resin composition.Furthermore, the present invention relates to an adhesive resincomposition, of which the adhesive force is not reduced even undercontact with high-temperature water, and a laminate having an excellentgas-barrier property and being capable of resisting a retort treatment,which is formed by using this adhesive resin composition.

(2) Description of the Related Art

An adhesive resin composition comprising three components, that is, astyrene resin, an ethylene/vinyl acetate copolymer resin and apolyethylene resin graft-modified with an unsaturated carboxylic acid ora derivative thereof has been publicly known. This adhesive resincomposition has an excellent adhesiveness between a metal and athermoplastic resin and also between a polyester resin and anethylene/vinyl acetate copolymer, which are used for a packagingmaterial or the like to be subjected a retort treatment.

This adhesive resin composition is used for a laminate sheath cablehaving a resin sheath arranged on the outer side of a barrier materialfor a cable and a cable core, and since this laminate sheath cable isexcellent in such characteristics as mechanical properties, corrosionresistance and moisture resistance, this cable is widely used at thepresent. In this laminate sheath cable, the above-mentioned adhesiveresin composition is used for bonding a metal tape composed of aluminum,copper or the like, to be used as the barrier layer, to a sheath resincomposed mainly of low-density polyethylene.

The laminate metal tape is generally prepared by extrusion lamination ofa metal and a sheath resin or bonding a metal layer to a fusion-bondingresin layer film and a sheath resin layer film. In case of conventionalfusion-bonding resins, streaks are often formed on the laminatedfusion-bonding resin layer.

These streaks are formed because of local changes of the thickness ofthe fusion-bonding resin layer and the presence of these streaksdegrades the adhesion between the metal and sheath resin and reduces theappearance characteristics of the product. Moreover, cracks are formedin a thin portion of the fusion-bonding resin layer and even theperformances of the product are reduced.

In (Japanese Unexamined Patent Publication No. 61-296044, we previouslyproposed a thermoplastic resin composition capable of preventingformation of streaks in the fusion-bonding resin layer, which comprises97 to 45 parts by weight of an ethylene/vinyl acetate copolymer, 30 to 1parts by weight of a styrene polymer resin, 15 to 1 parts by weight ofpolyethylene graft-modified with an unsaturated carboxylic acid or aderivative thereof and 30 to 1 parts by weight of a monovinyl aromatichydrocarbon/olefin block copolymer. When a laminate metal tape isprepared by using this thermoplastic resin composition as thefusion-bonding resin, streaks are not formed in the fusion bonding resinlayer, but the adhesiveness between the metal and a resin sheath layeris not completely satisfactory.

Accordingly, development of an adhesive resin composition which canprevent formation of streaks in the fusion-bonding (adhesive) resinlayer and can give an excellent adhesiveness between a metal and a resinsheath layer is eagerly desired.

Although the above-mentioned adhesive resin composition is used for theproduction of a laminate of a polyester resin and a gas-barrier resin tobe used for a packaging vessel or the like and shows a goodadhesiveness, if a heat treatment such as a high-temperature fillingtreatment or a retort treatment is carried out at the production of thislaminate or at the time of eating or drinking a content in the packagingvessel, the adhesive force is sometimes reduced by heating, resulting inpeeling of the layer and reduction of the gas permeation resistance.

As the adhesive resin composition capable of retaining a high adhesiveforce between layers of a laminate even after a high-temperaturetreatment such as a high-temperature filling treatment or a retorttreatment, we previously proposed in Japanese Unexamined PatentPublication No. 64-45445 an adhesive resin composition comprising (a) 95to 50% by weight of an ethylene/α-olefin copolymer having a melt flowrate of 0.1 to 50 g/10 min, a density of 0.850 to 0.900 g/cm³, anethylene content of 75 to 95 mole % and an X-ray crystallinity lowerthan 30%, (b) 5 to 50% by weight of an ethylene/vinyl acetate copolymerhaving a melt flow rate of 0.1 to 50 g/10 min and a vinyl acetatecontent of 5 to 40% by weight, and (c) 1.0 to 30% by weight, based onthe sum of components (a) and (b), of partially or wholly graft-modifiedpolyethylene having a grafting amount of an unsaturated carboxylic acidor a derivative thereof of 0.05 to 15% by weight, a melt flow rate of0.1 to 50 g/10 min, a density of 0.900 to 0.980 g/cm³ and an X-raycrystallinity of at least 30%, wherein the grafting ratio of thecomposition as a whole is 0.01 to 3% by weight, the melt flow rate ofthe composition as a whole is 0.1 to 50 g/10 min and the crystallinityof the composition as a whole is lower than 35%. In this patentpublication, we also proposed a laminate comprising a polyester orpolycarbonate layer, an intermediate layer composed of this adhesiveresin composition and a saponified olefin/vinyl acetate copolymer layer.

The above-mentioned adhesive resin composition has an excellentadhesiveness at normal temperature after a high-temperature treatment,but interlaminar peeling is sometimes caused in the above-mentionedlaminate during a high-temperature filling treatment or a retorttreatment.

Accordingly, development of an adhesive resin composition capable ofcompletely preventing occurrence of interlaminar peeling in a laminateeven under a high-temperature filling treatment or a retort treatment isdesired.

SUMMARY OF THE INVENTION

The present invention is to solve the above-mentioned problems of theconventional techniques, and it is a primary object of the presentinvention to provide an adhesive resin composition capable of preventingformation of streaks in a fusion-bonding resin layer and giving anexcellent adhesiveness between a metal and a thermoplastic resin sheathlayer, and a laminate formed by using this adhesive resin composition.

Another object of the present invention is to provide an adhesive resincomposition having such an excellent heat-resistant adhesiveness at ahigh temperature that occurrence of interlaminar peeling in a laminatecan be completely prevented even during a severe treatment such as ahigh-temperature filling treatment or a retort treatment, whilemaintaining a practical adhesion strength at normal temperature after ahigh-temperature treatment.

Still another object of the present invention is to provide a laminatehaving an excellent gas permeation resistance and not causinginterlaminar peeling at a high-temperature filling treatment or a retorttreatment, which is formed by bonding a polycarbonate layer orpolyalkylene terephthalate layer and a saponified ethylene/vinyl acetatecopolymer layer by using an adhesive resin composition as set forthabove.

A first adhesive resin composition having an excellent adhesivenessbetween a metal and a thermoplastic resin sheath layer according to thepresent invention comprises (a) 96 to 45 parts by weight of anethylene/vinyl acetate copolymer, (b) 30 to 1 parts by weight of astyrene polymer resin, (c) 15 to 1 parts by weight of polyethylenegraft-modified with an unsaturated carboxylic acid or a derivativethereof, (d) 20 to 1 parts by weight of a monovinyl aromatichydrocarbon/olefin block copolymer elastomer and (e) anethylene/α-olefin copolymer, the total amount of components (a), (b),(c), (d) and (e) being 100 parts by weight.

A first laminate formed by using the above-mentioned first adhesiveresin composition according to the present invention comprises a layerof a metal such as aluminum, copper or iron, a layer of a thermoplasticresin such as a polyamide, a saponified ethylene/vinyl acetatecopolymer, polyethylene or a polyester, and a layer of the firstadhesive resin interposed between the two layers.

The second adhesive resin composition of the present invention, whichhas an excellent adhesiveness between a polyester resin such as apolyalkylene terephthalate or a polycarbonate and a gas-barrier resinsuch as a saponified ethylene/vinyl acetate copolymer, includes thefollowing four embodiments.

An adhesive composition of the first embodiment comprises 100 parts byweight of partially or wholly graft-modified polyethylene in which agrafting amount of an unsaturated carboxylic acid or a derivativethereof is 0.05 to 15% by weight, the soft polymer being a styreneelastomer.

An adhesive resin composition of the second embodiment comprises 100parts by weight of a soft polymer and 1 to 30 parts by weight ofpartially or wholly graft-modified polyethylene in which a graftingamount of an unsaturated carboxylic acid or a derivative thereof is 0.05to 15% by weight, the soft polymer comprising (a) 20 to 100% by weightof a styrene elastomer and (b) 80 to 0% by weight of an ethylene/αolefincopolymer having an ethylene content of 45 to 95 mole %.

An adhesive resin composition of the third embodiment comprises 100parts by weight of a soft polymer and 1 to 30 parts by weight ofpartially or wholly graft-modified polyethylene in which a graftingamount of an unsaturated carboxylic acid or a derivative thereof is 0.05to 15% by weight, the soft polymer comprising (a) 20 to 100% by weightof an ethylene/vinyl acetate copolymer having a vinyl acetate content of5 to 40% by weight.

An adhesive resin composition of the fourth embodiment comprises 100parts by weight of a soft polymer and 1 to 30 parts by weight ofpartially or wholly graft-modified polyethylene in which a graftingamount of an unsaturated carboxylic acid or a derivative thereof is 0.05to 15% by weight, the soft polymer comprising (a) 20 to 100% by weightof a styrene elastomer, (b) 0 to 80% by weight of an ethylene/α-olefincopolymer having an ethylene content of 45 to 95 mole % and (c) 0 to 80%by weight of an ethylene/vinyl acetate copolymer having a vinyl acetatecontent of 5 to 40% by weight.

The laminate of the present invention formed by the second adhesiveresin composition includes the following two embodiments.

A laminate of the first embodiment comprises (I) a polyalkyleneterephthalate resin layer, (II) an adhesive layer composed of a secondadhesive resin composition as set forth above and (III) a saponifiedolefin/vinyl acetate copolymer layer.

A laminate of the second embodiment comprises (I) a polycarbonate resinlayer, (II) an adhesive layer composed of a second adhesive resincomposition as set forth above and (III) a saponified olefin/vinylacetate copolymer layer.

Laminates of the first and second embodiments are prepared by meltingthe respective resins independently in different extruders, feeding themelts to a die having a three-layer structure and co-extruding them sothat the adhesive resin composition is interposed between the two otherresin layers, or by forming layers of two resins other than the adhesiveresin composition in advance and melt-extruding the adhesive resincomposition between the two layers.

DETAILED DESCRIPTION OF THE INVENTION

Adhesive resin compositions of the present invention, laminates formedby using these adhesive resin compositions and processes for thepreparation of these laminates will now be described.

(A) Adhesive Resin Compositions

Ethylene/vinyl acetate copolymer

The ethylene/vinyl acetate copolymer used in the present invention is aknown ethylene/vinyl acetate copolymer (EVA). In general, there is usedan ethylene/vinyl acetate copolymer having a melt flow rate [MFR(E),ASTM D-1238, E] of 0.1 to 50 g/10 min, preferably 1 to 30 g/10 min, anda vinyl acetate content of 5 to 40% by weight, preferably 8 to 11% byweight in case of the first adhesive resin composition or 10 to 35% byweight in case of the second adhesive resin composition. If anethylene/vinyl acetate copolymer having MFR within the above-mentionedrange is used, the melt viscosity is reduced, the moldability isimproved and the adhesiveness is increased, and especially in the caseof the second adhesive resin composition, the adhesiveness after aretort treatment can be further improved.

Styrene resin

The styrene polymer resin used for the second adhesive resin compositionof the present invention includes not only a homopolymer of styrene butalso polymers and copolymers of styrene, nuclear substitution productsthereof and substitution products of styrene formed by substitution atthe α-position of the double bond, such as chlorostyrene,dichlorostyrene, methylstyrene, dimethylstyrene and α-methylstyrene. Ingeneral, in the present invention, a styrene polymer resin having a meltflow rate [MFR(G), ASTM D-1238, G] of 0.1 to 50 g/10 min, preferably 1to 40 g/10 min, is used. If a styrene polymer resin having MFR (G)within the above-mentioned range is used, an adhesive resin compositionhaving an excellent extrusion moldability is obtained.

Graft-modified polyethylene

The graft-modified polyethylene used in the present invention ischaracterized in that the grafting amount of an unsaturated carboxylicacid or a derivative thereof is 0.01 to 15% by weight, preferably 0.1 to5% by weight in case of the first adhesive resin composition or 0.1 to10% by weight in case of the second adhesive resin composition, the meltflow rate (ASTM D-1238, condition E) is 0.1 to 50 g/10 min, preferably0.3 to 30 g/10 min, the density is 0.900 to 0.980 g/cm³, preferably0.905 to 0.970 g/cm³, and the X-ray crystalinity is at least 30%,preferably 35 to 75%.

In this graft polyethylene, the polyethylene is partially or whollygraft-modified. The graft-modified polyethylene can be a product formedby graft-modifying an ethylene/α-olefin copolymer of ethylene with aminor amount, for example, up to 5 mole %, of at least one otherα-olefin selected from propylene, 1-butene, 4-methyl-1-pentene,1-hexene, 1-octene and 1-decene.

The graft-modified polyethylene is obtained by partially or whollygraft-modifying polyethylene or an ethylene/α-olefin copolymer with anunsaturated carboxylic acid or a derivative thereof. As the unsaturatedcarboxylic acid and its derivative, there can be mentioned, for example,unsaturated carboxylic acids such as acrylic acid, maleic acid, fumaricacid, tetrahydrophthalic acid, itaconic acid, citraconic acid, crotonicacid, isocrotonic acid and Nadic acid®(endocis-bicyclo[2,2,1]hept-5-ene-2,3-dicarboxylic acid), derivativesthereof such as acid halides, amides, imides, anhydrides and esters. Asspecific examples of the derivative, there can be mentioned malenylchloride, maleimide, maleic anhydride, citraconic anhydride, monomethylmaleate, dimethyl maleate and glycidyl maleate. Among these compounds,an unsaturated dicarboxylic acid or its anhydride is preferably used,and maleic acid, Nadic acid® and acid anhydrides thereof are especiallypreferably used.

For the production of a modification product by graft copolymerizationof polyethylene with a grafting monomer selected from theabove-mentioned unsaturated carboxylic acids and derivatives, variousknown processes can be adopted. For example, there can be adopted aprocess in which polyethylene is melted, the grafting monomer is addedto the melt and graft polymerization is carried out, and a process inwhich a solution of the grafting monomer in a solvent is added and graftpolymerization is carried out. In each case, in order to increase thegrafting efficiency of the grafting monomer, the reaction is preferablycarried out in the presence of a radical initiator. The graftingreaction is generally carried out at a temperature of 60 ° to 350° C.The amount used of the radical initiator is generally 0.001 to 1 part byweight per 100 parts by weight of polyethylene. As the radicalinitiator, there can be mentioned organic peroxides and organicperesters such as benzoly peroxide, dichlorobenzoyl peroxide, dicumylperoxide, di-tert-butyl peroxide,2,5-dimethyl-2,5-di(peroxidobenzoato)hexyne-3,1,4-bis(tert-butylperoxy-isopropyl)benzene, lauroyl peroxide, tert-butylperacetate, 2,5-dimethyl-2,5-di(tert-butylperoxy)hexyne-3, 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane, tert-butylperbenzoate,tert-butylperphenyl acetate, tert-butyl perisobutyrate, tert-butylper-sec-octoate, tert-butyl perpivalate and cumyl perpivalate, and otherazo compounds such as azobisisobutyrinitrile and dimethylazoisobutyrate. Among these compounds, there are preferably used dialkylperoxides such as di-tert-butyl peroxide,2,5-dimethyl-2,5-di(tert-butylperoxy)-hexyne-3 and1,4-bis(tert-butylperoxyisopropyl)benzene.

Monovinyl aromatic hydrocarbon/olefin block copolymer elastomer (styreneelastomer)

The monovinyl aromatic hydrocarbon/olefin block copolymer elastomer(styrene elastomer) is a polymer having a linear or branched blockstructure having a monovinyl aromatic hydrocarbon polymer block on atleast one terminal thereof, which is represented by the general formulaof (A--B)_(n'),(A--B)_(n) A' or (A--B)_(m) X wherein A and A' representa monovinyl aromatic hydrocarbon polymer block, B represents an olefinpolymer block, n is an integer of from 1 to 5, m is an integer of from 2to 7 and X represents a polyfunctional compound having a valency of m.Styrene and α-methylstyrene are preferably used as the monovinylaromatic hydrocarbon, and styrene is especially preferably used. As theolefin, there can be mentioned conjugated diolefins such as butadieneand isoprene, and α-olefins such as ethylene, propylene and 1-butene.The polymer block formed by polymerization of a conjugated diolefin canbe hydrogenated. The block B may be composed of a copolymer of butadieneor isoprene with styrene or α-methylstyrene, so far as olefin units arecontained in a major amount. In the present invention, in the monovinylaromatic hydrocarbon/olefin block copolymer elastomer (d), the amount ofthe monovinyl aromatic hydrocarbon polymer blocks is generally 8 to 55%by weight and preferably 10 to 35% by weight. A block copolymer havingmonovinyl aromatic hydrocarbon polymer blocks on both of the terminalsis preferably used. These block copolymers are marketed, for example,under tradenames of Cariflex® TR and Kraton® G (each being a registeredtrade mark for a product supplied by Shell Chemicals).

Ethylene/α-olefin copolymer

The ethylene/α-olefin copolymer used in the present invention is anethylene/α-olefin random copolymer which is characterized in that themelt flow rate [MFR(E), ASTM D-1238, condition E] is 0.1 to 50 g/10 min,preferably 0.3 to 30 g/10 min, the density is 0.850 to 0.900 g/cm³,preferably 0.850 to 0.890 g/cm³, the ethylene content is 75 to 95 mole%, preferably 75 to 90 mole %, in case of the first adhesive resincomposition, or 45 to 95 mole %, preferably 45 to 90 mole %, in case ofthe second adhesive composition, and the X-ray crystallinity is lowerthan 30%, preferably lower than 25%.

If an ethylene/α-olefin copolymer having the above-mentionedcharacteristics is used, an adhesive resin composition having anexcellent adhesiveness can be obtained. Especially, in the secondadhesive resin composition, the adhesiveness after a retort treatmentand the adhesiveness to a polyolefin are highly improved.

An α-olefin having 3 to 20 carbon atoms is used as the α-olefinconstituting this ethylene/α-olefin copolymer. As specific examples,there can be mentioned propylene, 1-butene, 1-hexene,4-methyl-1-pentene, 1-octene, 1-decene, 1-tetradecene and 1-octadecene.These α-olefin can be used alone or in the form of a mixture of two ormore of them.

The ethylene/α-olefin copolymer generally has a melting point (ASTMD-3418) lower than 100° C.

Mixing ratios

In the first adhesive resin composition of the present invention, theethylene/vinyl acetate copolymer (a) is used in an amount of 96 to 45parts by weight, preferably 85 to 50 parts by weight, the styrenepolymer resin (b) is used in an amount of 30 to 1 parts by weight,preferably 25 to 5 parts by weight, the graft-modified polyethylene (c)is used in an amount of 15 to 1 parts by weight, preferably 10 to 2parts by weight, the monovinyl aromatic hydrocarbon/olefin blockcopolymer elastomer (d) is used in an amount of 20 to 1 parts by weight,preferably 18 to 3 parts by weight, and the ethylene/α-olefin copolymer(e) is used in an amount of 20 to 1 parts by weight, 18 preferably to 3parts by weight, per 100 parts by weight of the total amount ofcomponents (a) through (e).

In the second adhesive resin composition of the present invention, thegraft-modified polyethylene is used in an amount of 1 to 30 parts byweight, preferably 2 to 28 parts by weight, per 100 parts by weight ofthe soft polymer.

In the first embodiment of the second adhesive resin composition, thesoft polymer is a styrene elastomer.

In the second embodiment of the second adhesive resin composition, astyrene elastomer and an ethylene/α-olefin copolymer are used incombination as the soft polymer. In this case, the soft polymercomprises 20 to 100% by weight, preferably 20 to 90% by weight, of thestyrene elastomer, and 0 to 80% by weight, preferably 10 to 80% byweight, of the ethylene/α-olefin copolymer, with the proviso that thetotal amount of the styrene elastomer and the styrene/α-olefin copolymeris 100% by weight.

In the third embodiment of the second adhesive resin composition, astyrene elastomer and an ethylene/vinyl acetate copolymer are used incombination as the soft polymer. In this case, the soft polymercomprises 20 to 100% by weight, preferably 20 to 90% by weight, of thestyrene elastomer and 0 to 80% by weight, preferably 10 to 80% byweight, of the ethylene/vinyl acetate copolymer, with the proviso thatthe total amount of the styrene elastomer and the ethylene/vinyl acetatecopolymer is 100% by weight.

In the fourth embodiment of the second adhesive resin composition, anethylene/α-olefin copolymer and an ethylene/vinyl acetate copolymer canbe used together with the styrene elastomer as the soft polymer. In thiscase, the soft polymer comprises 20 to 100% by weight, preferably 20 to90% by weight, of the styrene elastomer, 0 to 80% by weight, preferably10 to 70% by weight of the ethylene/α-olefin copolymer, and 0 to 80% byweight, preferably 10 to 70% by weight, of the ethylene/vinyl acetatecopolymer, with the proviso that the total amount of the styreneelastomer, the ethylene/α-olefin copolymer and the ethylene/vinylacetate copolymer is 100% by weight.

The second adhesive resin composition of the present invention comprisesthe styrene elastomer and the graft-modified polyethylene asindispensable components, and the grafting ratio of the entirecomposition is 0.01 to 3% by weight, preferably 0.05 to 2.5% by weight.MFR of the total composition is 0.1 to 50 g/10 min, preferably 0.2 to 40g/10 min, and the crystallinity of the total composition is lower than35%.

The adhesive resin composition of the present invention is prepared bymixing the above-mentioned amounts of the above-mentioned components byknown mixing means such as a Henschel mixer, a V-type blender, a ribbonblender or a tumbling blender, or by melt-kneading the above mixture bya single-screw extruder, a twin-screw extruder, a kneader or a Banburymixer and granulating or pulverizing the melt-kneaded mixture.

Additives customarily used for thermoplastic resins, for example, aheat-resistant stabilizer, a weathering stabilizer, an antistatic agent,a lubricant, a slip agent, a nucleating agent, a dye or pigment and aplasticizer such as a hydrocarbon oil, can be added to the adhesiveresin composition of the present invention, so far as the attainment ofthe objects of the present invention is not hindered.

(B) Laminates and Process for Preparation Thereof

In the laminate forming by using the first adhesive resin composition,the adhesive resin composition is interposed between a metal such asaluminum, copper or iron and a thermoplastic resin such as a polyamide,a saponified ethylene/vinyl acetate copolymer, polyethylene, apolycarbonate or a polyester.

This laminate can be prepared, for example, according to a process inwhich a film having a thickness of 10 to 200 μm is formed from theadhesive resin composition, the film is set between adherends, that is,the metal and thermoplastic resin, and fusion bonding is carried out toeffect lamination, or a process in which the adhesive resin compositionand the thermoplastic resin as the adherent are independently melted indifferent extruders and the melts are extruded through a multi-layer dieto effect lamination.

The laminate formed by using the second adhesive resin composition ofthe present invention comprises (I) a polyalkylene terephthalate resinor polycarbonate resin layer, (II) an adhesive layer composed of thesecond adhesive resin composition and (III) a saponified olefin/vinylacetate copolymer layer.

The layer (I) constituting the laminate of the present invention iscomposed of a member selected from a polyalkylene terephthalate resinand a polycarbonate resin.

The polyester resin used is a polyester comprising units of at least onedihydroxyl compound selected from aliphatic glycols such as ethyleneglycol, propylene glycol, 1,4-butanediol, neopentyl glycol andhexamethylene glycol, alicyclic glycols such as cyclohexanedimethanoland aromatic dihydroxyl compounds such as bisphenol, and units of atleast one dicarboxylic acid compound selected from aromatic dicarboxylicacids such as terephthalic acid, isophthalic acid and2,6-naphthalene-dicarboxylic acid, aliphatic dicarboxylic acids such asoxalic acid, succinic acid, adipic acid, sebacic acid andundecanedicarboxylic acid and alicyclic dicarboxylic acids such ashexahydroterephthalic acid. The polyester can be modified with a smallamount of a polyhydroxyl compound or polycarboxylic acid having avalency of at least 3, such as a triol or a tricarboxylic acid, so faras the polyester shows thermoplastic properties. As the thermoplasticpolyester, there can be mentioned polyethylene terephthalate,polybutylene terephthalate and a polyethylene isophthalate/terephthalatecopolymer.

The polycarbonate resin used in the present invention includes variouspolycarbonates and copolycarbonates obtained by reacting dihydroxylcompounds with phosgene or diphenyl carbonate according to knownprocesses. As specific examples of the dihydroxyl compound, there can bementioned hydroquinone, resorcinol, 4,4'-dihydroxydiphenylmethane,4,4'-dihydroxydiphenylethane, 4,4'-dihydroxydiphenyl-n-butane,4,4'-dihydroxydiphenylheptane, 4,4'-dihydroxydiphenylphenylmethane,4,4'-dihydroxy-diphenyl-2,2-propane (bisphenol A),4,4'-dihydroxy-3,3'-dimethyldiphenyl-2,2'-propane,4,4'-dihydroxy-3,3'-diphenyldiphenyl-2,2-propane,4,4'-dihydroxydichlorophenyl-2,2-propane,4,4'-dihydroxydiphenyl-1,1-cyclopentane,4,4'-dihydroxydiphenyl-1,1-cyclohexane,4,4'-dihydroxydiphenylmethylphenylmethane,4,4'-diphydroxydiphenylethyl-phenylmethane,4,4'-dihydroxydiphenyl-2,2,2-trichlorol, 1-ethane,2,2'-dihydroxydiphenyl, 2,6-dihydroxynaphthalane, 4,4'-dihydroxydiphenylether, 4,4'-dihydroxy-3,3'-dichlorodiphenyl ether and4,4'-dihydroxy-2,5-diethoxyphenyl ether. Among these compounds,4,4'-dihydroxy-diphenyl-2,2-propane (bisphenol) is preferably used,because the formed polycarbonate has excellent mechanical properties andtransparency.

The above-mentioned adhesive resin composition is used for the adhesivelayer (II) of the laminate of the present invention.

The layer (III) constituting the laminate of the present invention iscomposed of a saponified olefin/vinyl acetate copolymer. A saponifiedolefin/vinyl acetate copolymer may be prepared by saponifying anolefin/vinyl acetate copolymer having an olefin content of 15 to 60mole%, preferably 25 to 50 mole%, to a saponification degree of at least50%, preferably at least 90%. If the olefin content is within theabove-mentioned range, thermal decomposition is hardly caused and meltforming can be easily performed, and the drawability, water resistanceand gas permeation resistance are highly improved. If the saponificationdegree is higher than 50%, the gas permeation resistance is highlyimproved.

As the olefin to be copolymerized with vinyl acetate, there can bementioned ethylene, propylene, 1-butene, 1-hexane, 4-methyl-1-pentene,1-octane, 1-decene, 1 tetradecene and 1-octadecene. Among them, ethyleneis especially preferably used in view of the mechanical stability andmoldability.

For the preparation of the laminate of the present invention, there canbe adopted, for example, a co-extrusion process in which thepolyalkylene terephthalate resin or polycarbonate resin, the adhesiveresin composition and the saponified olefin/vinyl acetate copolymer aremelted in different extruders, the melts are supplied to a die having athree-layer structure and the melts are co-extruded so that the adhesiveresin composition forms an intermediate layer, or a sandwich laminationprocess in which the polyalkylene terephthalate resin or polycarbonateresin and the saponified olefin/vinyl acetate copolymer are formed intolayers in advance and the adhesive resin composition is melt-extrudedbetween the two layers. In view of the interlaminer bonding force, theco-extrusion process is preferably adopted. The co-extrusion processincludes a T-die method using a flat die and an inflation method using acircular die. Either a single manifold type using a black box or amultiple-manifold type can be used as the flat die. Other known dies canalso be used in the inflation method.

The thickness of each layer of the laminates can be appropriatelydetermined according to the intended use. In general, when the laminateis used as a sheet of film, it is preferred that the thickness of thepolyalkyl terephthalate resin or polycarbonate resin layer be 0.02 to 5mm, the thickness of the adhesive layer be 0.01 to 1 mm and thesaponified olefin/vinyl acetate copolymer layer be 0.01 to 1 mm.

The laminate of the present invention can further have a structure of(I)/(II)/(III)/(II)/(I) in which layers (I) are arranged on both thesides, or a structure further comprising a polyolefin layer, forexample, a structure of polypropylene/(II)/(III)/(II)/(I) orpolyethylene/(II)/(III)/(II)/(I).

The present invention will now be described in detail with reference tothe following examples that by no means limit the scope of theinvention.

EXAMPLE 1

High-density polyethylene (Hizex supplied by Mitsui PetrochemicalIndustries, Ltd.; MFR (E)=5.5 g/10 min) was reacted with maleicanhydride to obtain graft-modified polyethylene having a maleicanhydride content of 0.5% by weight, MFR (E) of 3.0 g/10 min and a gelcontent lower than 0.1%.

To 5 parts by weight of the graft-modified polyethylene were added 60parts by weight of an ethylene/vinyl acetate copolymer (vinyl acetatecontent=10% by weight, MFR (E)=9.0 g/10 min; hereinafter referred to as"EVA"), 20 parts by weight of polystyrene (supplied under tradename of"Denka Styrol GP200" by Denki Kagaku Kogyo, MFR (G)=25 g/10 min;hereinafter referred to as "PS"), 10 parts by weight of a polybutadieneblock-hydrogenated polystyrene/polybutadiene/polystyrene block copolymer(supplied under tradename of "Krayton G1652" by Shell Chemicals, styrenecontent=29% by weight) and 5 parts by weight of an ethylene/propylenecopolymer [MFR (E)=1.0 g/10 min, ethylene content=80 mole%, X-raycrystallinity=5%, density=0.870 g/cm³ ], and the mixture wasmelt-kneaded and granulated by using an extruder provided with a Dulmagescrew having a diameter of 40 mm to obtain a composition (1).

The obtained composition (1) was melted at 200° and formed into a presssheet having a thickness of 3 mm by using a compression molding machine.The physical properties (MFR and the density) of the press sheet weredetermined. The obtained results are shown in Table 1.

A fusion-bonding film having a thickness of 50 μm was formed from thecomposition (1) by using a molding machine provided with a T-die havinga diameter of 30 mm, and the presence or absence of streaks on theformed film was checked. By using this fusion-bonding film, an aluminumfoil was bonded to a polyethylene sheet under conditions described belowto obtain a laminate.

Structure

A foil/film of composition (1)/polyethylene sheet

A foil: 200 μm in thickness, 10 mm in width and 15 cm in length

Composition (1) film: 50 μm in thickness, 25 mm in width and 15 cm inlength

Polyethylene sheet: 2 mm in thickness, 25 mm in width and 15 cm inlength.

Bonding Conditions

Temperature: 200° C.

Pressure: 6 kg/cm²

Time: 3 minutes.

A test piece having a width of 10 mm and a length of 15 cm for measuringthe bonding strength was cut out from the laminate by using a knife, andthe 180° peel strength was measured at a pulling speed of 200 mm/min.

The obtained results are shown in Table 2.

EXAMPLE 2

To 5 parts by weight of the maleic anhydride-grafted high-densitypolyethylene used in Example 1 were added 70 parts by weight of EVA, 10parts by weight of PS, 10 parts by weight of Krayton G and 5 parts byweight of the ethylene/propylene copolymer, and the mixture wasmelt-kneaded and granulated in the same manner as described in Example 1to obtain a composition (2).

The physical properties (MFR and the density) of a press sheet of theobtained composition (2) are shown in Table 1.

In the same manner as described in Example 1, a fusion-bonding filmhaving a thickness of 50 μm was formed from the composition (2) and thepresence or absence of streaks was checked, and an aluminumfoil/polyethylene sheet laminate was obtained by using this film and the180° peel strength was measured.

The obtained results are shown in Table 2.

EXAMPLE 3

To 10 parts by weight of the maleic anhydride-grafted high-densitypolyethylene used in Example 1 were added 60 parts by weight of EVA, 15parts by weight of PS, 5 parts by weight of Krayton G and 10 parts byweight of an ethylene/propylene copolymer, and the mixture wasmelt-kneaded and granulated in the same manner as described in Example 1to obtain a composition (3).

The physical properties (MFR and the density) of a press sheet of theobtained composition (3) are shown in Table 1.

In the same manner as described in Example 1, a fusion-bonding filmhaving a thickness of 50 μm was formed from the composition (3) and thepresence or absence of streaks was checked, and an aluminumfoil/polyethylene sheet laminate was obtained by using this film and the180° peel strength was measured.

The obtained results are shown in Table 2.

EXAMPLE 4

To 5 parts by weight of the maleic anhydride-grafted high-densitypolyethylene used in Example 1 were added 65 parts by weight of EVA, 15parts by weight of PS, 10 parts by weight of Krayton G and 5 parts byweight of an ethylene/butene copolymer [MFR (E)=3.5 g/10 min, ethylenecontent=85 mole %, crystallinity=15%, density=0.885 g/cm³ ], and themixture was melt-kneaded and granulated in the same manner as describedin Example 1 to obtain a composition (4).

The physical properties (MFR and the density) of a press sheet of theobtained composition (4) are shown in Table 1.

In the same manner as described in Example 1, a fusion-bonding filmhaving a thickness of 50 μm was formed from the composition (4) and thepresence or absence of streaks was checked, and an aluminumfoil/polyethylene sheet laminate was obtained by using this film and the180° peel strength was measured.

The obtained results are shown in Table 2.

COMPARATIVE EXAMPLE 1

To 5 parts by weight of the maleic anhydride-grafted high-densitypolyethylene used in Example 1 were added 80 parts by weight of EVA, 15parts by weight of PS and the mixture was melt-kneaded and granulated inthe same manner as described in Example 1 to obtain a composition (5).

The physical properties (MFR and the density) of a press sheet of theobtained composition (5) are shown in Table 1.

In the same manner as described in Example 1, a fusion-bonding filmhaving a thickness of 50 μm was formed from the composition (5) and thepresence or absence of streaks was checked, and an aluminumfoil/polyethylene sheet laminate was obtained by using this film and the180° peel strength was measured.

The obtained results are shown in Table 2.

COMPARATIVE EXAMPLE 2

To 5 parts by weight of the maleic anhydride-grafted high-densitypolyethylene used in Example 1 were added 70 parts by weight of EVA, 15parts by weight of PS and 10 parts by weight of Krayton G, and themixture was melt-kneaded and granulated in the same manner as describedin Example 1 to obtain a composition (6).

The physical properties (MFR and the density) of a press sheet of theobtained composition (6) are shown in Table 1.

In the same manner as described in Example 1, a fusion-bonding filmhaving a thickness of 50 μm was formed from the composition (6) and thepresence or absence of streaks was checked, and an aluminumfoil/polyethylene sheet laminate was obtained by using this film and the180° peel strength was measured.

The obtained results are shown in Table 2.

COMPARATIVE EXAMPLE 3

To 5 parts by weight of the maleic anhydride-grafted high-densitypolyethylene used in Example 1 were added 70 parts by weight of EVA, 15parts by weight of PS and 10 parts by weight of the ethylene/propylenecopolymer, and the mixture was melt-kneaded and granulated in the samemanner as described in Example 1 to obtain a composition (7).

The physical properties (MFR and the density) of a press sheet of theobtained composition (7) are shown in Table 1.

In the same manner as described in Example 1, a fusion-bonding filmhaving a thickness of 50 μm was formed from the composition (7) and thepresence or absence of streaks was checked, and an aluminumfoil/polyethylene sheet laminate was obtained by using this film and the180° peel strength was measured.

The obtained results are shown in Table 2.

COMPARATIVE EXAMPLE 4

To 5 parts by weight of the maleic anhydride-grafted high-densitypolyethylene used in Example 1 were added 60 parts by weight of EVA, 15parts by weight of PS, 10 parts by weight of high-density polyethylene[MFR (E)=8.2 g/10 min, density=0.965 g/cm³, crystallinity=81%], and themixture was melt-kneaded and granulated in the same manner as describedin Example 1 to obtain a composition (8).

The physical properties (MFR and the density) of a press sheet of theobtained composition (8) are shown in Table 1.

In the same manner as described in Example 1, a fusion-bonding filmhaving a thickness of 50 μm was formed from the composition (8) and thepresence or absence of streaks was checked, and an aluminumfoil/polyethylene sheet laminate was obtained by using this film and the180° peel strength was measured.

The obtained results are shown in Table 2.

                                      TABLE 1                                     __________________________________________________________________________                                       Comparative                                                                          Comparative                                                                          Comparative                                                                          Comparative                  Measurement                                                                           Example                                                                            Example                                                                            Example                                                                            Example                                                                            Example                                                                              Example                                                                              Example                                                                              Example                      Method  1    2    3    4    1      2      3      4                     __________________________________________________________________________    MFR(E) ASTM D 1238                                                                           5.2  4.5  6.8  6.4  7.4    5.2    5.9    6.5                   (g/10 min)                                                                    Density                                                                              ASTM D 1505                                                                           0.94 0.94 0.94 0.94 0.95   0.94   0.94   0.95                  (g/cm.sup.3)                                                                  Strain at                                                                            ASTM D 638                                                                            --   --   --   --   74     --     --     86                    Yield Point                                                                   (kg/cm.sup.2)                                                                 Tensile Force                                                                        ASTM D 638                                                                            97   110  100  99   64     130    96     103                   at Break                                                                      Point                                                                         (kg/cm.sup.2)                                                                 Elongation                                                                           ASTM D 638                                                                            490  500  490  530  190    500    510    430                   (between                                                                      bench marks)                                                                  (%)                                                                           Shore Hard-                                                                          ASTM D 2240                                                                           48   45   46   49   48     44     43     48                    ness (D)                                                                      Vicat Sof-                                                                           ASTM D 1525                                                                           64   62   63   65   72     69     64     72                    tening Point                                                                  (°C.)                                                                  __________________________________________________________________________

                  TABLE 2                                                         ______________________________________                                               Formation 180° Peel Strength (kg/10 mm)                                of streaks                                                                              (bonding temperature = 200° C.)                       ______________________________________                                        Example 1                                                                              ◯                                                                             5.2                                                      Example 2                                                                              ◯                                                                             4.9                                                      Example 3                                                                              ◯                                                                             5.2                                                      Example 4                                                                              ◯                                                                             5.1                                                      Comparative                                                                            X           5.1                                                      Example 1                                                                     Comparative                                                                            ◯                                                                             3.0                                                      Example 2                                                                     Comparative                                                                            X           4.0                                                      Example 3                                                                     Comparative                                                                            ◯                                                                             2.5                                                      Example 4                                                                     ______________________________________                                         Note                                                                          ◯ not observed                                                    X observed                                                               

EXAMPLE 5

A 5-layer sheet was formed under conditions described below by using acomposition (1) comprising 100 parts by weight of a styrene elastomer(Krayton G 1652 supplied by Shell Chemicals; hereinafter referred to as"SEBS") and 10 parts by weight of maleic anhydride-grafted modifiedpolyethylene (MFR=1.0 g/10 min, density=0.925 g/cm³, crystallinity=52%,butene content=3.6 mole %, maleic anhydride grafting amount=1.0 g/100 gof polymer; hereinafter referred to as "MAH-PE-1"), a polycarbonate(Panlite L-1250 supplied by Teijin Kasei; hereinafter referred to as"PC"), a saponified ethylene/vinyl acetate copolymer (Kuraray Eval EP-Fsupplied by Kuraray, MFR=1.3 g/10 min, density=1.19 g/cm³, ethylenecontent=32 mole %; hereinafter referred to as "EVOH"), and polypropylene(Hipol F 401 supplied by Mitsui Petrochemical Industries, Ltd.;hereinafter referred to as "PP").

Sheet structure:

PC/(1)/EVOH/(1)/PP.

Layer thicknesses (μm):

80/50/50/50/80.

Extruders:

40-mm screw diameter extruder, 260° C. (for PC)

30-mm screw diameter extruder, 250° C. [for (1)]

30-mm screw diameter extruder, 210° C. (for EVOH)

40-mm screw diameter extruder, 230° C. (for PP).

With respect to the obtained 5-layer sheet, the interfacial bondingstrength (FPC, g/15 mm) between the layer of (1) and the EVOH layer andthe interfacial bonding strength (FEVOH, g/15 mm) between the EVOH layerand the layer of (1) were measured at a peeling atmosphere temperatureof 23° or 80° C. and a peeling speed of 300 mm/min according to theT-peel test.

The sheet was subjected to a retort treatment at 131° C. for 30 minutes.Then, the T-peel test was carried out under the same conditions asdescribed above.

The obtained results are shown in Table 3.

EXAMPLE 6

A 5-layer sheet was obtained and the T-peel test was carried out in thesame manner as described in Example 5 except that a composition (2)comprising 75 parts by weight of SEBS, 25 parts by weight of anethylene/propylene random copolymer (MFR=1.0 g/10 min, ethylenecontent=80 mole %, density=0.865 g/cm³, crystallinity=4%; hereinafterreferred to as "EPR-1") and 10 parts by weight of MAH-PE-1 was usedinstead of the composition (1) used in Example 5.

The obtained results are shown in Table 3.

Then, a 5-layer sheet was formed by using the composition (2), theabove-mentioned EVOH, polyethylene terephthalate (formed by adding acrystallization promoter to J135 supplied by Mitsui Pet; hereinafterreferred to as "PET") and PP under conditions described below.

Sheet structure:

PET/(2)/EVOH/(2)/PP.

Layer thicknesses (μm):

80/50/50/50/80.

Extruders:

40-mm screw diameter extruder, 280° C. (for PET)

30-mm screw diameter extruder, 250° C. (for (2))

30-mm screw diameter extruder, 210° C. (for EVOH)

40-mm screw diameter extruder, 230° C. (for PP).

With respect to the obtained sheet, the interfacial bonding strength(FPET, g/15 mm) between the PET layer and the layer of (2) and theinterfacial bonding strength (FEVOH, g/15 mm) between the EVOH layer andthe layer of (2) were measured under the same conditions as describedabove with respect to PC.

The obtained results are shown in Table 4.

EXAMPLE 7

A 5-layer sheet was obtained and the T-peel test was carried out in thesame manner as described in Example 6 except that a composition (3)comprising 80 parts by weight of SEBS, 20 parts by weight of anethylene/vinyl acetate copolymer (MFR=2.5 g/10 min, vinyl acetatecontent=25% by weight; hereinafter referred to as "EVA-1") and 10 partsby weight of MAH-PE-1 was used instead of the composition (2) used inExample 6.

The obtained results are shown in Tables 3 and 4.

EXAMPLE 8

A 5-layer sheet was obtained and the T-peel test was carried out in thesame manner as described in Example 6 except that a composition (4)comprising 40 parts by weight of SEBS, 45 parts by weight of anethylene/1-butene random copolymer (MFR=3.5 g/10 min, ethylenecontent=89 mole %, density=0.885 g/cm³, crystallinity=15%; hereinafterreferred to as "EBR-1"), 15 parts by weight of EVA-1 and 20 parts byweight of MAH-PE-1 was used instead of the composition (2) used inExample 6.

The obtained results are shown in Tables 3 and 4.

EXAMPLE 9

A 5-layer sheet was obtained and the T-peel test was carried out in thesame manner as described in Example 5 except that a composition (5)comprising 20 parts by weight of SEBS, 60 parts by weight of EBR-1, 20parts by weight of EVA-1 and 10 parts by weight of MAH-PE-1 was usedinstead of the composition (1) used in Example 5.

The obtained results are shown in Table 3.

EXAMPLE 10

A 5-layer sheet was obtained and the T-peel test was carried out in thesame manner as described in Example 5 except that a composition (6)comprising 60 parts by weight of SEBS, 20 parts by weight of EBR-1, 20parts by weight of EVA-1 and 10 parts by weight of MAH-PE-1 was usedinstead of the composition (1) used in Example 5.

The obtained results are shown in Table 3.

COMPARATIVE EXAMPLE 5

A 5-layer sheet was obtained and the T-peel test was carried out in thesame manner as described in Example 5 except that a composition (7)comprising 100 parts by weight of EBR-1 and 10 parts by weight ofMAH-PE-1 was used instead of the composition (1) used in Example 5.

The obtained results are shown in Table 3.

COMPARATIVE EXAMPLE 6

A 5-layer sheet was obtained and the T-peel test was carried out in thesame manner as described in Example 5 except that a composition (8)comprising 85 parts by weight of EBR-1, 15 parts by weight of EVA-1 and10 parts by weight of MAH-PE-1 was used instead of the composition (1)used in Example 5.

The obtained results are shown in Table 3.

COMPARATIVE EXAMPLE 7

A 5-layer sheet was obtained and the T-peel test was carried out in thesame manner as described in Example 5 except that a composition (9)comprising 40 parts by weight of SEBS, 45 parts by weight of EBR-1 and15 parts by weight of EVA-1 was used instead of the composition (1) usedin Example 5.

The obtained results are shown in Table 3.

                                      TABLE 3                                     __________________________________________________________________________                      PC/EVOH Multi Layer Sheet                                                     FPC (g/15 mm width)    FEVOH (g/15 mm width)                       Recipe (parts by        23° C.          23° C.                  weight) of Adhesive                                                                      23° C.                                                                        80° C.                                                                       atmosphere after                                                                        23° C.                                                                       80° C.                                                                        atmosphere after               Resin Composition                                                                        atmosphere                                                                           atmosphere                                                                          retort treatment                                                                        atmosphere                                                                          atmosphere                                                                           retort                  __________________________________________________________________________                                                          treatment               Example 5                                                                            SEBS   100 940    920   390       690   630    350                            MAH-PE-1                                                                             10                                                              Example 6                                                                            SEBS   75  1250   930   860       830   720    790                            EPR-1  25                                                                     MAH-PE-1                                                                             10                                                              Example 7                                                                            SEBS   80  1190   1010  750       450   410    440                            EVA-1  20                                                                     MAH-PE-1                                                                             10                                                              Example 8                                                                            SEBS   40  860    440   590       450   400    440                            EBR-1  45                                                                     EVA-1  15                                                                     MAH-PE-1                                                                             20                                                              Example 9                                                                            SEBS   20  690    350   810       520   370    500                            EBR-1  60                                                                     EVA-1  20                                                                     MAH-PE-1                                                                             10                                                              Example 10                                                                           SEBS   60  830    670   570       390   320    410                            EBR-1  20                                                                     EVA-1  20                                                                     MAH-PE-1                                                                             10                                                              Comparative                                                                          EBR-1  100 910    180   110       1300  210    1030                    Example 5                                                                            MAH-PE-1                                                                             10                                                              Comparative                                                                          EBR-1  85  1600   120   1390      460   170    450                     Example 6                                                                            EVA-1  15                                                                     MAH-PE-1                                                                             10                                                              Comparative                                                                          SEBS   40  750    610   430        90    50     10                     Example 7                                                                            EBR-1  45                                                                     EVA-1  40                                                              __________________________________________________________________________

                                      TABLE 4                                     __________________________________________________________________________                      PET/EVOH Multi-Layer Sheet                                                    FPET (g/15 mm width)   FEVOH (g/15 mm width)                       Recipe (parts by        23° C.          23° C.                  weight) of Adhesive                                                                      23° C.                                                                        80° C.                                                                       atmosphere after                                                                        23° C.                                                                       80° C.                                                                        atmosphere after               Resin Composition                                                                        atmosphere                                                                           atmosphere                                                                          retort treatment                                                                        atmosphere                                                                          atmosphere                                                                           retort                  __________________________________________________________________________                                                          treatment               Example 6                                                                            SEBS   75  960    890   880       810   700    800                            EPR-1  25                                                                     MAH-PE-1                                                                             10                                                              Example 7                                                                            SEBS   80  840    320   730       460   420    410                            EVA-1  20                                                                     MAH-PE-1                                                                             10                                                              Example 8                                                                            SEBS   40  520    380   510       460   390    430                            EBR-1  45                                                                     EVA-1  15                                                                     MAH-PE-1                                                                             20                                                              __________________________________________________________________________

In Examples 5 through 10 and Comparative Examples 5 through 7, thecrystallinity and density were measured according to the followingprocedures.

(1) Preparation of Sample

The sheet was heated at 180° C. by a hot press for 10 minutes and wasrapidly cooled by a cooling press (water cooling) to prepare a sample.

(2) Crystallinity

The crystallinity of the sample obtained in (1) above was determined bythe X-ray diffractometry.

(3) Density

The density of the sample was measured at 23° C. according to thedensity gradient tube method.

As is apparent from the results of the foregoing examples, since thefirst adhesive resin composition comprises (a) an ethylene/vinyl acetatecopolymer, (b) a styrene polymer resin, (c) graft-modified polyethylene,(d) a monovinyl aromatic hydrocarbon/olefin block copolymer elastomerand (e) an ethylene/α-olefin copolymer at a specific ratio, streaks arenot formed at the extrusion molding, and a fusion-bonding (adhesive)film having a good appearance is obtained. Furthermore, the adhesiveresin composition of the present invention can give an excellentadhesiveness between a metal and a thermoplastic resin sheath layer.

Accordingly, the adhesive resin composition of the present invention canbe suitably used as a melt adhesive for laminates of laminate sheathcables and films of various packaging materials.

When the second adhesive composition of the present invention is usedfor bonding (I) a layer of a polyalkylene terephthalate resin orpolycarbonate resin and (III) a layer of a saponified olefin/vinylacetate copolymer, the layers (I) and (III) can be so tightly bondedthat peeling of the layers (I) and (III) is not caused even underhigh-temperature conditions as adopted for a high-temperature fillingtreatment or a retort treatment, and a practically sufficient bondingstrength can be maintained at normal temperature after thishigh-temperature treatment.

Accordingly, a laminate comprising the layers (I) and (III) bonded byusing the adhesive resin composition of the present invention has a highresistance to permeation of gases such as oxygen and therefore, thelaminate has excellent properties as a retortable food packagingmaterial.

We claim:
 1. A laminate structure useable as a retortable packagingmaterial comprising (I) a layer of a polyalkylene terephthalate resin ora polycarbonate resin, (III) a saponified olefin/vinyl acetate copolymerlayer, and interposed therebetween (II) a layer of an adhesive resincomposition, said adhesive resin composition comprising 100 parts byweight of a soft polymer and 1 to 30 parts by weight of partially orwholly graft-modified polyethylene which has a melt flow rate (ASTMD-1238, condition E) of from 0.1 to 50 g/10 min, a density of 0.900 to0.980 g/cm³, and an X-ray crystallinity of at least 30%, and in whichthe graft monomer is an unsaturated carboxylic acid or a derivativethereof, and wherein the amount of the graft monomer is 0.05 to 15% byweight, wherein the soft polymer comprises (a) 20 to 90 parts by weightof a styrene/ethylene-butene/styrene block copolymer elastomer havingstyrene polymer blocks on both of the terminals of the polymer molecule,and (b) 80 to 10 parts by weight of an ethylene/α-olefin copolymerhaving an ethylene content of 45 to 95 mole %, a melt flow rate (ASTMD-1238, condition E) of from 0.1 to 50 g/10 min, a density of from 0.850to 0.900 g/cm³ and an X-ray crystallinity of lower than 30%.
 2. Thelaminate structure of claim 1 wherein the graft-modified polyethylenehas a melt flow rate (ASTM D-1238, condition E) of from 0.3 to 30 g/10min, a density of 0.905 to 0.970 g/cm³, and an X-ray crystallinity of atleast 35 to 75%, said ethylene/α-olefin copolymer having a melt flowrate (ASTM D-1238, condition E) of from 0.3 to 30 g/10 min, a density offrom 0.850 to 0.890 g/cm³, and an X-ray crystallinity of lower than 25%.3. A laminate structure useable as a retortable packaging materialcomprising (I) a layer of a polyalkylene terephthalate resin or apolycarbonate resin, (III) a saponified olefin/vinyl acetate copolymerlayer, and interposed therebetween (II) a layer of an adhesive resincomposition, said adhesive resin composition comprising 100 parts byweight of a soft polymer and 1 to 30 parts by weight of a partially orwholly graft-modified polyethylene which has a melt flow rate (ASTMD-1238, condition E) of from 0.1 to 50 g/10 min, a density of 0.900 to0.980 g/cm³, and an X-ray crystallinity of at least 30%, and in whichthe graft monomer is an unsaturated carboxylic acid or derivativethereof, and the amount of the monomer is 0.05 to 15% by weight, whereinthe soft polymer comprises (a) 20 to 80 parts by weight of astyrene/ethylene-butene/styrene block copolymer elastomer having styrenepolymer blocks on both of the terminals of the polymer molecule, (b) 10to 70 parts by weight of an ethylene/α-olefin copolymer having anethylene content of 45 to 95 mole %, a melt flow rate (ASTM D-1238,condition E) of from 0.1 to 50 g/10 min, a density of from 0.850 to0.900 g/cm³ and an X-ray crystallinity lower than 30%, and (c) 10 to 70parts by weight of an ethylene/vinyl acetate copolymer having a vinylacetate content of 5 to 40% by weight.
 4. A laminate structure useableas a retortable packaging material comprising a metal layer, athermoplastic resin layer, and interposed therebetween a layer of anadhesive resin composition, said adhesive resin composition comprising(a) 96 to 45 parts by weight of an ethylene/vinyl acetate copolymer, (b)30 to 1 parts by weight of a styrene polymer resin, (c) 15 to 1 parts byweight of polyethylene graft-modified with an unsaturated carboxylicacid or a derivative thereof, (d) 20 to 1 parts by weight of a monovinylaromatic hydrocarbon/olefin block copolymer elastomer and (e) anethylene/α-olefin copolymer having an ethylene content of 45 to 95 mole%, a melt flow rate (ASTM D-1238, condition E) of from 0.1 to 50 g/10min, a density of from 0.850 to 0.900 g/cm³ and an X-ray crystallinityof lower than 30%, the total amount of components (a), (b), (c), (d),and (e) being 100 parts by weight.
 5. The laminate structure of claim 4wherein said adhesive resin composition comprises (a) 80 to 50 parts byweight of said ethylene/vinyl acetate copolymer, (b) 25 to 5 parts byweight of said styrene polymer resin, (c) 10 to 2 parts by weight ofsaid polyethylene graft-modified with an unsaturated carboxylic acid ora derivative thereof, (d) 18 to 3 parts by weight of said blockcopolymer elastomer which is a polybutadiene block-hydrogenatedpolystyrene/polybutadiene/polystyrene block copolymer elastomer and (e)18 to 3 parts by weight of said ethylene/α-olefin random copolymer,wherein the ethylene content is 75 to 95 mole %, the total amount ofcomponents (a), (b), (c), (d) and (e) being 100 parts by weight.
 6. Thelaminate structure of claim 5 which comprises (a) 60 to 70 parts byweight of the ethylene/vinyl acetate copolymer, (b) 10 to 20 parts byweight of the styrene polymer resin, (c) 5 to 10 parts by weight of thegraft-modified polyethylene, (d) 5 to 10 parts by weight of the blockcopolymer elastomer, and (e) 5 to 10 parts by weight of theethylene/α-olefin random copolymer.